Circuit/System Testing

NOTE:

The global positioning system (GPS) requires a clear line of sight to the sky to operate properly. It may take up to 15 minutes for the Nav Radio to acquire a GPS signal. In most cases the GPS will not have reception near tall buildings or inside structures.

Ignition OFF, disconnect the navigation antenna coax cable connector at the A11 Radio. Connect the EL-49903 GM OnStar Antenna Diagnostic Tool Kit to the A11 Radio, place the test antenna on the roof of the vehicle.
Ignition ON, radio ON, navigation selected.
Verify the NO GPS symbol/message is not displayed
- If the NO GPS symbol/message is displayed
  Replace the radio
- If the NO GPS symbol/message is not displayed
Ignition OFF, disconnect the radio navigation coax cable at the T4P navigation antenna.
Verify the radio navigation coax cable passes the coax cable component test. Refer to Component Testing.
- If the coax cable does not pass the test
  Replace the coax cable
- If the coax cable passes the test
Test or replace the T4P Navigation Antenna